Senior ISSE Lead — Mission-Critical Security Systems

L3Harris Technologies, Inc.; Greenville (TX); Hybrid; USD 120,000 - 160,000; Full time

Job summary

L3Harris Technologies is seeking an experienced Information Systems Security Engineer (ISSE) to join our Sensor Infrastructure team in Greenville, TX. The ideal candidate will bring deep expertise in security requirements, vulnerability management, and Authorization to Operate (ATO) documentation to strengthen mission-critical systems.

The role involves collaborating with stake- holders across IT and engineering, delivering briefing materials, and guiding security design choices with measurable

Qualifications

• Active US TS/SCI security clearance.
• DoD 8140.03 IASAE Level 2 certification.
• Bachelor’s Degree and 9+ years of relevant experience.
• Graduate Degree and 7+ years of related experience.
• In lieu of a degree, 13+ years of related experience.
• Experience authoring and reviewing security requirements.
• Experience improving security processes, systems, and controls.
• Experience developing and reviewing verification plans, test procedures, and test reports.
• Experience with vulnerability scanning tools (Nessus, Tenable, ACAS).
• Experience with ISR platforms, mission systems, sensors, payload integration, BMC2.
• Experience with documentation, interface control, and requirement management tools.
• Experience in trade studies and hardware/software selection decisions.
• Ability to communicate and influence security practices across organizational boundaries.
• Demonstrated ability to communicate and influence security practices across organizational boundaries.

Responsibilities

• Author and review security requirements, ensuring alignment with applicable frameworks and policies.
• Identify and implement significant improvements to security processes, systems, and controls.
• Prepare and deliver technical briefing materials for leadership and stakeholders.
• Lead system requirements management, decomposition, traceability, verification, and validation.
• Define, analyze, allocate, and manage system, subsystem, and component requirements.
• Evaluate requirements flow-down, definition quality, and traceability.
• Conduct trade studies across hardware, software, and system design alternatives.
• Support hardware selection for mission systems, processing, networking, sensors, storage, and infrastructure.
• Develop and review verification plans, test procedures, and test reports.
• Resolve complex technical issues and support final platform trade-off decisions with Chief Engineers.
• Work with IT and other functions to enforce security strategy.
• Translate complex technical issues into actionable insights for stakeholders.
• Contribute to security standards, architectural guidance and policy improvements.
• Contribute to security standards, architectural guidance and policy improvements.

Skills

Security engineering

Vulnerability scanning

ATO documentation

Requirements management

Leadership

Policy compliance

Stakeholder briefing

Education

Master's degree or higher

Bachelor's degree

13+ years experience (no degree)

DoD 8140 IASAE Level 2

Tools

Nessus

ACAS

DOORS

Cameo

JIRA

MBSE tools

Job description

L3Harris Technologies is seeking an experienced Information Systems Security Engineer (ISSE) to join our Sensor Infrastructure team in Greenville, TX. The ideal candidate will bring deep expertise in security requirements, vulnerability management, and Authorization to Operate (ATO) documentation to strengthen mission-critical systems.

The role involves collaborating with stake- holders across IT and engineering, delivering briefing materials, and guiding security design choices with measurable